Kill switch for M/T 2011 Chevy Cruze Eco
 

I realize I may have posted this in the wrong section originally, so I am posting my questions and updates here because I realized its more appropriate.

I have a 2011 Cruze Eco and have been trying hard to improve my gas mileage in the city. My best tank is 46.8 mpg.

I have started doing EOC, but obviously there are two conditions I am trying to avoid,
1. Killing my ignition switch.
2. Resetting the DIC, especially when coasting at 55 mph speeds I lose (or think I lose) the distant traveled while the DIC resets.

I started reading up on what to kill. I decided to do fuel injectors. So looking at my under hood fuse box, mini fuses 8 and 9 are tied to the injectors.
Fuse 8 = Fuel Injection (Car Manual) (on the box cap it says injector 1 and 3)
Fuse 9 = Fuel Injection / Ignition system (Car manual) ((on the box cap it says injector 2 and 4)

Last night I started testing. I started by pulling Fuse 9, the engine died instantly and DIC didn’t reset. I tested this a couple more times with no codes showing up. Then I tried fuse 8. It surprisingly did nothing for the entire minute the fuse was removed.

Reviewing the layout I also decided to try fuse 5, which is the Ignition System only. The car died instantly, however, when I plugged it back in I could hear something switching. I assumed this was the solenoid or something because I couldn’t see it without removing stuff. Figured it was better to stay away from anything that audibly switched on and off like that.

So, if I understand this correctly. I need to wire an inline fuse (15amp) to a momentary switch inside the car. Connect it to the box with some 18 AWG wire. Then test.

Questions I have are:

Any educated guess on what fuse 8 is for?
Is my assumption about fuse 5 sound?

The main reason I want to EOC over DFCO is DFCO on this car (Waiting for confirmation) does not seem to work at speeds less than 20 MPH, and on the 35 MPH street, I do drop below 20 on a coast to a light. Also I read that over 40 MPH DECO is not as effective, of course this probably depends on the car and the gear ratio? So the window for DFCO seems too small to me to really gain efficiency.

Any suggestions or insights before I continue? I could use any feedback.

Quazar -

It sounds like you have the right fuse with #9. Are you also posting on a Chevy Cruze forum (you don't have to tell them why)? Sometimes a fuse is used for more than one thing. The mini fuses are dedicated to one thing most of the time, but the big fuses serve multiple roles.

CarloSW2

I wonder how healthy it is for your turbo to cut it's oil supply very often, does the car come with a system to provide cool down oil to the turbo? I know they are available aftermarket.

Are you referring to the Intercooler? If so yes there is one.

As a point of clarification, when you say cutting the oil to the turbo, do you mean by killing the fuel? Isn't the only difference on the engine between doing a EOC and just stopping the car and turning it off, that the car is in motion and can be used to bump start? Other than this, in both cases isn't the engine, and turbo off?

I don't think there would be any problems with the turbo cooling as long as you don't beat the hell out of it and shut down the engine right after.

I suppose that if you're trying to hypermile this car as much as possible you won't spool that turbo much!

Never owned a turbo car, but I though you are supposed to let them idle before shutting the engine down so the turbo's bearing get to coast down/cool a little while the engine oil is still pumping thru the bearing. An alternative to that is you add a oil accumulator that discharges after the engine is shut down, it then releases it's oil into the bearings.

If P&G w/EOC you'll be fairly aggressive on throttle while pulsing then shutting down the engine with turbo spooled cutting it's oil supply while it's still spinning. Myself I'd be a little leary of doing that.

Quazar, did you ever get this to work? I'm interested as well. The main issue I'm having is coming up with a reasonably acceptable solution for the cabin mounted kill switch. I want it to work well but look decent at the same time.

rooster, I agree with your P&G concerns... shutting the engine down during or right after acceleration will stop both coolant and oil flow to the turbo while it is still spinning fairly quick. I don't P&G and don't ever intend to, my plan is to disable the engine when coasting or to avoid idling.

What are your average speeds like? It's not uncommon for me to get 45, 46MPG in my Focus (in the summer) going back and fourth to my parents. It's a 140 mile round trip that I've done numerous times, and it's an easy 45MPG trip.

My focus has no modifications and is no where near as good as the Cruze Eco for final drive and aerodynamics.

FWIW, the Cruze turbo is thermally cooled by a "thermo-siphoning" coolant system, or so GM claims...there is no actual mechanical coolant pump. It's been discussed over on the CruzeTalk forum.

My best two full tanks have been 46 and 48 MPG, both were a majority of commuting and short trips with a couple of short highway jaunts thrown in. This is in winter weather, though, so I expect to improve on these numbers slightly in summer. I have a short 23km (14mi) commute and only fill every 9-10 days on average, so my driving varies quite a bit during a whole tank.

My best one-way highway trip so far was ~54 MPG, but that was also in winter weather doing ~58-60 MPH. Based on what others are reporting in better weather, at speeds 55-60 MPH I would expect to get somewhere between 54-58 MPG (US gallons, of course), maybe a little higher if my increased tire pressure and lowered suspension add any benefits.